The folder can be on an external drive too but the challenge is that I normally don't keep the disk connected at all times. Google Drive allows you to sync a folder outside the main Google Drive folder. As much I trust Google, I still want to keep a local copy of all of my files and I want it to seamlessly sync with the cloud. I now have more data in Google Drive than can fit into my Mac's 500 GB of built-in storage. It's not well documented, so I run a few tests to understand how exactly Google Drive works with external disks. How Google Drive works with external disks
